Amplitude adjuster in an electronic timepiece

ABSTRACT

The mechanical vibrator of an electronic timepiece is provided with a transistorized drive circuit having a driving coil and a sensing coil. A vibration amplitude adjusting resistor unit is provided in the circuit and is comprised of a series of resistor elements and conductive elements arranged originally with a predetermined number of connectors which may be readily interrupted and/or a predetermined number of connectors having non-conductive gaps which may readily be closed to select the desired resistance to increase or decrease the amplitude of vibration.

United States Patent Takamune [451 Apr. 11, 1972 [54] AMPLITUDE ADJUSTER IN AN [5 6] References Cited I T P C UNITED STATES PATENTS [72] Invent: Takamune Japan 2,707,234 4/1955 Dostal ..58/23 TF [73] Assignee: Citizen Watch Co., Ltd., Tokyo, Japan 3,351,833 11/1967 Gerum ..58/23 A [22] Filed: 1970 Primary ExaminerRichard B. Wilkinson [2 L No 64,716 Assistant ExaminerEdith C. Simmons Attorney-Sughrue, Rothwell, Mion, Zinn & Macrxaak [30] Foreign Application Priority Data 57 ABSTRACT g- 1969 Japan -44/78261 The mechanical vibrator of an electronic timepiece is pro- 1969 P vided with a transistorized drive circuit having a driving coil Aug. 25, 1969 Japan ..44/80599 d a Sensing il. A vibration amplitude adjusting resistor unit is provided in the circuit and is comprised of a series of re- [52] US. Cl. ..58/23 A, 331/109 sister elements and conductive elements arranged originally IIll-Cl "1304c 3/00,H03b with a predetermined number of connectors which may be [5 8] Field of Search ..58/23, 23 A, 28, 28 A; readily interrupted and/or a predetennined number of con- 3 132 nectors having non-conductive gaps which may readily be closed to select the desired resistance to increase or decrease the amplitude of vibration.

8 Claims, 16 Drawing Figures PATENTEDAPR 11 I972 3,654,757

SHEET 2 OF 4 Bio PATENTEDAPR H I972 v 3. 654,757

SHEET 3 [IF 4 AMPLITUDE ADJUSTER IN AN ELECTRONIC TIMEPIECE This invention relates generally to improvements in a battery-driven electronic watch, and more specifically it relates to improvements in and relating to the adjuster mechanism for proper setting of the amplitude of the mechanical vibrator commonly employed in this kind of electronic watch and formed mostly and rcpresentatively into a balance wheel, tuning fork, tuning lead or the like oscillatory member.

In the above kind of electronic watch, the mechanical vibrator is controlled in its electromagnetically driven oscillatory motion by means of at least a semiconductor switching circuit element. Unavoidable variation will be encountered in the characteristic data or constants of these switching elements and other related circuit parts when manufactured on an industrial scale, which invites naturally a corresponding deviation of the oscillation amplitude of the mechanical vibrator from its design value, even though a sincere attention is given to the selection of the precisely manufactured circuit elements. This kind of operational fluctuation of the mechanical vibrator is invited further by the unavoidable inferior workmanship of the magnets, coils and the like which constitute in combination the electromechanical motion converter mechanism, as well as by the loading variation in general of the conventional watch gear train acting, as the load to the converter.

According to the conventional technique for attaining a predetermined oscillating period of the mechanical vibrator, various circuit elements including the conventional sensing and drive coils are exchanged by proper ones and frequent and tedious adjustments must be made for properly modifying the mechanical load conditions relative to the vibrator.

For satisfying the aforementioned various requirements, a conventional measure is to employ a variable resistor inserted in the electronic circuit. But, it has been experienced with a substantial limitation in miniaturizing such type of resistors so as to adapt them for use in smaller size timepieces, especially smaller electronic watches.

It has been further experienced in the use of such variable resistors with inferior electrical contact which result in a faulty operation of the electronic timepiece.

A further drawback inherent in the employment of these variable resistors resides in the insufficient resistance to outside shocks to which the timepiece would frequently be subjected in practical use thereof by its wearer. The unsatisfactory shockproofness will require frequent readjustment of the once set resistance value for recovery thereof.

Another conventional technique for performing occasionally required adjustment of the amplitude of a mechanical vibrator of an electronic timepiece is to reduce the amplitude from a certain high value to an optimal one by modifying an adjustable resistance circuit comprising a plurality of resistance elements and connected in series with the drive coil of the motion converter, for increasing its overall resistance value to a selected higher value.

The main object of the present invention is to provide an improved electronic circuit assembly capable of substantially the aforementioned conventional various drawbacks.

A further object of the invention is to provide an electronic circuit assembly for increasing or decreasing the overall resistance of the adjustable resistance circuit, or to increase or decrease the practical amplitude of the mechanical vibrator as desired to a certain limited range.

These and further objects, features and advantages of the invention will become more apparent when read the following detailed description of the invention by reference to the accompanying drawings.

In the drawings:

FIG. 1 is a plan view of a battery-driven movement of an electronic timepiece, embodying the principles of the inven tion.

FIG. 2 is a schematic convection diagram of an electronic circuit employed in the circuit assembly according to the invention.

FIG. 3 is an enlarged plan view of a part of the timepiece movement shown in FIG. 1, showing a main unit comprising several main working circuit elements of the circuit assembly according to the invention.

FIG. 4 is a back surface view of the unit shown in FIG. 3.

FIG. 5 is a side view of the unit shown in FIGS. 3 and 4.

FIG. 6 is an enlarged plan view of a modification of the amplitude adjusting resistor from that contained in the circuit shown in FIG. 2.

FIG. 7 is a modified circuit from that shown in FIG. 2, wherein the amplitude adjusting resistor has been somewhat modified and two transistors in place of the sole one shown in the foregoing has been connected into a multivibrator.

FIG. 8 is a still further modified circuit arrangement from that shown in FIG. 7, wherein, however, two sets of amplitude adjusting resistors have been embodied.

FIG. 9 is a plan view of the front surface of a specifically constructed circuit unit representing the wiring connections shown in FIG. 8.

FIG. 10 is a plan view of the rear surface of the circuit unit shown in FIG. 9.

FIG. 11 is a side view of the circuit unit shown in FIG. 9 and 10.

FIG. 12 is a plan view of part of an electronic watch, embodying a circuit assembly as a second embodiment of the invention.

FIG. 13 is an example of an imaginary amplitude adjuster circuit stading outside of the framework of the invention.

FIG. 14 is a still further modified circuit from that shown in FIG. 2.

FIG. 15 is a circuit of which a dotted line block includes the circuit elements shown in FIG. 12.

FIG. 16 is a rear side view of the circuit unit shown in FIGS. 12 and 15.

Referring now to the accompanying drawings, especially FIGS. 1-5, a first embodiment of the present invention will be described in detail.

In the battery-driven electronic watch generally shown at 10, the numeral 11 represents a disc-type battery which is mounted in a corresponding recess 12 formed on the conventional plate 13 of the watch, said battery being held in position by means of a retainer strip 14 which is attached firmly, yet detachably to the plate 13 by means of fixing screws 15 and The numeral 17 represents a printed plastic, ceramic or the like insulator board which is firmly mounted in a correspondingly shaped recess 18 formed on the plate 13 by means of fixing screws 19 and 20 passing through the corresponding reception holes 27 and 28 formed through the plastic board 17. On the rear surface of the latter, a transistor 21 is fixedly attached by means of its conducting leads 23, 24 and 38. In the similar way, a condenser 22 is fixedly attached to the board 17 by means of its leads 25 and 26. These transistors 21 and condenser 22 are fed with current from said battery 1 1, as most clearly seen from FIG. 2.

The numeral 29 is a coil carrier made into an insulator plate such as plastic, ceramic or the like which carries combined coil assembly comprising a sensing coil element 30 and a drive coil element 31 of the conventional design shown schematically in FIG. 2, although not specifically shown in FIG. 1, these coils being so designed and arranged to electromagnetically cooperate with a sensing and a drive permanent magnet shown at and 136, respectively, and carried rigidly by a balance wheel 32.

The watch is provided naturally with a conventional gear train, although not shown, several gears of which are rotatably supported respective bearings 129-132 rigidly mounted in a mounting plate 33, the latter being fixedly attached to the plate 13 by means of a plurality of set screws 134. Coil carrier 29 is rigidly attached to the plate 13 by means of a set screw shown at 35. Although not shown, the gear train is adapted to be driven from the balance wheel 32, as is commonly known in the conventional balance wheel type electronic watch.

In the circuit diagram shown in FIG. 2, sensing coil 30 is electrically connected at its one side through lead 36, junction 34, lead 26, condenser 22, lead 25, junction 37 and lead 38 to the base electrode of the transistor 21. The opposite side of the sensing coil 30 is electrically connected through lead 39, junction 40, lead 41, junction 42 and lead 43 to the positive side of the battery 11. The negative side of the latter is electrically connected through lead 44, junction 45 and lead 24 to the emitter electrode of transistor 21, while the collector electrode of the latter is connected through lead 23, junction 48 and lead 49 to an amplitude adjusting resistor generally shown only schematically in FIG. 2 at 50. The opposite side of the resistor 50 is connected through lead 51, junction 52 and lead 53 to one side of the drive coil 31, the opposite side of which is connected through a lead 54 to a junction 42. Bias resistor 55 is connected at its both side through respective leads 56 and 57 to junctions 37 and 40, respectively.

The junction 40 shown in FIG. 2 is constituted by said set screw 20 in practice in the case of the present embodiment. The leads 39 and 54 shown in FIG. 2 is constituted in common by the set screw 35 in the present embodiment. Further in practice, the lead 43 is constituted by the retainer strip 14 and the junction 42 is constituted by the screws and 16. Lead 41 is constituted a part of the plate 13.

Resistors 50 and 55 have been formed on the insulator board 17 by printing or evaporatively depositing a kind of conventional resistance paste comprising, as an example, palladium, silver and metal oxide, and baking at 700800 C.

Leads or conducting parts such as at 49, 56 and 57 and conducting parts contained in the amplitude adjusting resistor 50 to be described have been formed as shown by the conventional circuit printing process on the insulator board 17 with a known conducting paste containing silver, gold, platinum or the like and then again baked at a temperature between 700 and 800 C.

In the both operations, the baking temperature can be modified depending upon the nature and kind of the material of the insulator boards.

For modifying the resistance value of the bias resistor 55, one or more lateral cuts are mechanically formed, yet in a non-interrupting way.

The amplitude adjusting resistor 50 comprises a conducting part generally shown at 60 and an elongated resisting part generally shown at 61. The former part 60 comprises a series of axial conducting elements a which may be continuous as seen at the right-hand half thereof when seen in FIG. 3 or may be interrupted at c as seen at the left-hand half thereof. In addition, each of said axial conductive elements a is united with a lateral conductive element b which has an ample length so as to cross the resistor strip 61. The resistor elements 11,, d and d, are excluded, in this case, from the circuit by virtue of the electrical connection of the related conductor elements a" connected in the longitudinal direction one after another and as shown, thereby providing a branch-off resistor comprising said resistor elements d -d On the contrary, the remaining resistance elements u and u are included in the circuit by virtue of two interrupted points c between the related longitudinal conductive elements a. Naturally, the number of the resistor elements d,--a and u,u are only illustrative and may be increased or decreased as desired at the production stage.

By increasing, at the desired adjusting stage, the number of the gaps or interruptions c," by use of a diamond chip or tool, as an example, the overall resistance of the resistor 50 may be correspondingly increased for decreasing the oscillatory amplitude of the balance wheel 32.

On the contrary, when it is desired to decrease the overall resistance value for reducing the oscillatory amplitude of the balance wheel 32, the number of the interruptions c may be correspondingly reduced by fusing the gap or gaps as desired by applying thereat the conducting paste.

According to our experience, a specific relation generally exists between the adjusting resistor as at 50 and the variation conductive elements a, a" and a in the oscillation amplitude of a mechanical vibrator, and therefore, by splitting the resistor strip into equal resistor elements, the amplitude can be adjusted stepwise each time by a certain constant value.

As an example, a resistance value 500 ohms may correspond to a variation of amplitude angle 20 in a practical electronic watch. By selecting the each stage of the resistor strip 61, the amplitude angle of the balance wheel may be reduced 20 by providing an open gap at the conductive element a" corresponding to (1,. When opened at the initial two successive conductive elements a corresponding to d, and d the amplitude will be reduced by 40, and so on.

On the contrary, the amplitude will be increased by 20 by closing conductingly one of the open gaps c. A closure of two gaps c, the amplitude will be increased by 40 and so In the modified resistor arrangement shown in FIG. 6, opened resistor elements u -u having interrupted longitudinal respectively, are connected in series with a series of closed resistor elements d -d by means of the two continuous conducting leads 62 and 63. Central lead 63 extends to the junction 48, while the outer lead 62 extends to the junction 52.

In this arrangement, the interrupted series of resistor elements u,-u is excluded in effect from the circuit, while the parallel connected series of resistor elements ti -d are included in effect in the circuit. The areas of these resistor elements represent respective and thus different resistance values.

By closing the related gaps c in a successive way, the amplitude of the mechanical vibrator will be correspondingly increased.

On the contrary, the oscillation amplitude will be correspondingly decreased by interrupting in the aforementioned way the resistor elements a -d Also, in this case, the number of the resistor elements can be increased or decreased so as to meet with occasional demands, as the case may be.

In the present parallel arrangement, the closure or opening a resistor element will affect substantially more effectively upon the modifying effect to the oscillation amplitude of the mechanical vibrator represented representatively by the balance wheel 32.

In the circuit arrangement shown in FIG. 7, two transistors 21a and 21b, two bias resistors 55a and 55b, and two condensers 22a and 22b are employed, in place of the corresponding singular elements 21, 22 and 55. Battery is shown at 11a. These circuit elements are arranged to provide a multivibrator as known per se. In this case, coils 30a and 31a are arranged and mounted as shown in FIG. 1 at 30;3 l, but these coils act in the present embodiment as sensing means and drive means in an alternating way by virtue of the multivibrator connection as above mentioned.

When the present circuit operates as the multivibrator, condensers 22a;22b and resistors 55a;55b act as time constant elements as will be easily supposed by any person skilled in the art.

A block shown in chain-dotted line represents an amplitude adjusting resistor which corresponds to that shown at 50in FIG. 2 and at 70 in FIG. 6.

This resistor unit 100 comprises a series of resistor elements r r r and r, which are connected laterally with longitudinal conductor elements a,, a a and a, by lateral conductor elements b b b and b.,, respectively. In the shown position, the overall resistance of the unit 100 will be substantially nil by virtue of all the longitudinal conductive elements a -a, conductive in combination. By interrupting these conductive elements a a, successfully, the resistor elements r,-r, are included in effect in the circuit and relative to the coil 30a when the latter acts as drive means and in a successive manner. On the contrary, by interrupting the lateral conductive elements b,b, successively, these resistor elements are also included in effect in the circuit relative to the same coil 30a when the latter operates as sensing means.

When the coil 30a acts as the drive means, the oscillation amplitude will become decreased correspondingly with increase of the resistance value at 100, and vice versa.

0n the contrary, when the coil 30a acts as the sensing means, the oscillation amplitude will become increased correspondingly with increase of the resistance value at 100, and vice versa.

In the arrangement shown in FIG. d, main circuit components are substantially similar to those employed in FIG. 7 so that similar parts have been shown with same reference numeral. In the present arrangement, however, resistors 55a and 55b corresponding to those denoted 55a and 55b in FIG. 7 are connected in parallel to condensers 22a and 22b, respectively, for simplifying the respective connections. The function is substantially same, however, as before.

Coils 30a and 31a corresponding to those 30a and 31a in the foregoing, are connected in a somewhat different manner from the foregoing, but, their function is not altered appreciably thereby. Transistors 21a and 21b are connected to the plate 13 through manual switch 71 and battery 11b.

In the present arrangement, it will be seen that two similar amplitude adjusting resistors 100a and corresponding to that shown at I00 in the foregoing are provided and arranged as shown. Substantially all the main working components are mounted on an insulator board similar to that shown at 17 in the foregoing, as schematically shown by a dotted line block 170 and as specifically shown in FIGS. 9-lll.

The relative operation between the adjusting resistor 100a and the coil 31a is perfectly same as before. The remaining coil 30a is also influenced by the newly provided resistor 10% in the similar manner. Therefore, the amplitude adjusting function is doubled in this case in comparison with that obtainable with the foregoing arrangement shown in FIG. 7.

In the following two numerical examples will be shown by reference to the arrangement shown in FIG. 7.

Now assuming that r =r =r =r =l killo-ohm; and an electronic watch shown substantially in FIG. 1 was driven in a practical experiment. The results were as follows:

In the next experiment, resistor elements were set in the following way:

r l killo-ohm;r 2 killo-ohms;

r 3 killo-ohms; r 4 killo-oh'rns.

Interrupted Positions b1 b1; b2 brba brbr killo-ohrns iripiit u d iii r gi 5 14 29 Bi Interrupted Positions a1 a; a 4 killo-ohms fififiliu ii iifiilfiaaxjj3:1: 11 21 32 43 In the arrangement shown in the foregoing in FIGS. 8-41, the resistor elements were set as follows:

The provision of switch 71 serves for interruption of the circuit in case of non-use of the watch, thereby preventing an excess and meaningless power consumption.

In the arrangement shown in FIGS. l2, l5 and 16, the amplitudeadjusting circuit comprises a sensing coil 30a" and a drive coil 31a", a condenser 220, a resistor 550, an adjusting resistor unit 1000, a switch 710 and a transistor 21c are provided and arranged as shown. The structure and function can be substantially understood by reference of the corresponding foregoing reference numerals 21, 30, 31, 22, 55, 71 and and their related foregoing disclosure.

By interrupting the lateral conductive leads c -c by successively advancing in the direction of an arrow A, the overall re sistance of the resistor unit 10% for the drive coil 310 will be increased and thus the oscillation amplitude of the mechanical vibrator, not shown but being able to arrange in the similar way in FIG. 1, will be correspondingly decreased.

On the contrary, when the successive interruption of the lateral conductive leads c -c by advancing in the direction of a small arrow B, the overall resistance of the resistor unit 1000 relative to the sensing coil 30a" will be correspondingly increased so that the amplitude of the mechanical vibrator such as at 32 in FIG. I will be correspondingly increased.

Junctions 34c, 45c, 52c and 72 in FIG. 15 are shown also in FIG. 16. These functions 34c, 45c and 520 are similar to those shown at 34, 4,5 and 52 in the foregoing, while a new junction 72 is shown only in FIGS. 15 and 16. Battery and switch 71a will serve as before as was illustrated in the foregoing at 11 and 71, respectively.

An imaginary circuit arrangement standing outside of the framework of the invention is shown in FIG. 13. The constituents 11c, 21c, 22c, 30a and 550 are same in their structure and function, as was referred to FIG. 15. The amplitude adjusting resistor unit is shown at 100d. From this figure, it will be seen even by adapting any possible way for interrupting the related conductive elements, the overall resistance of the unit will become modified only in the resistance increasing direction.

The arrangement shown in FIG. 14 is substantially similar to that shown in FIG. 5. In this, the resistor 55c and the battery 11c are differently'connected from the arrangement in FIG. 15, but the function is substantially similar. The interrupting direction A will provide the same results as those in the case of A. The reversed operation in the direction B will produce similar results as was referred to in the case of B.

What is claimed is:

I. In an electronic timepiece of the type comprising a mechanical vibrator, permanent magnet means carried thereby, a transistor drive circuit having a transistor means, a sensing coil and a driving coil with said coils being electromagnetically coupled with said permanent magnet means, the improvements comprising an amplitude adjusting resistor unit inserted in said circuit and comprising an insulator base, at least a series of film resistor elements and a series of conducting film elements arranged parallel thereto and deposited on said base, each of said resistor elements being electrically connected by a laterally arranged and equally deposited conducting film connector with a corresponding one of said series of conducting film elements, said conducting connectors being so arranged that by interrupting them selectively the amplitude of said vibrator may be modified in a stepped manner in the desired direction of amplitude increase or decrease.

2. In an electronic timepiece as claimed in claim 1, wherein said series of conducting elements are originally provided with a plurality of interruptions between said conducting elements, whereby when a selected number of these interruptions are closed by the application of a conducting paste the overall resistance of said resistor unit is reduced to increase the practiselam lwls siths e s rt lyibetea 3. In an electronic timepiece as claimed in claim 1, wherein said series of conducting elements are originally provided with a plurality of conducting joints between said conducting elements, whereby when a selected number of these joints are opened mechanically, the overall resistance of said resistor unit is increased to decrease the practical amplitude of the mechanical vibrator.

4. In an electronic timepiece as claimed in claim 1, wherein said series of film resistor elements is comprised of an elongated strip of resistor material.

5. In an electronic timepiece as set forth in claim 1, wherein the drive circuit comprises two transistors which are connected into a multivibrator with each other such that the two coils which are provided in the circuit each act as the sensor and the driver in an alternating way.

6. In an electronic timepiece as set forth in claim 5, wherein said resistor unit is connected at one end to the collector electrode of one of the transistors and the opposite end of said resistor unit is connected to the base electrode of the remaining resistor as well as one of said coils.

7. In an electronic timepiece as set forth in claim 6, wherein said resistor unit is doubled in a symmetrical way.

8. In an electronic timepiece as claimed in claim 1, wherein said resistor unit is so inserted in the circuit that by interrupting said lateral conductive connectors selectively in one direction the overall resistance of the resistor unit is increased correspondingly relative to the drive coil element and by interrupting said lateral conductive connectors selectively in the opposite direction said overall resistance relative to the sensing coil is increased correspondingly.

* i li i 1k 

1. In an electronic timepiece of the type comprising a mechAnical vibrator, permanent magnet means carried thereby, a transistor drive circuit having a transistor means, a sensing coil and a driving coil with said coils being electromagnetically coupled with said permanent magnet means, the improvements comprising an amplitude adjusting resistor unit inserted in said circuit and comprising an insulator base, at least a series of film resistor elements and a series of conducting film elements arranged parallel thereto and deposited on said base, each of said resistor elements being electrically connected by a laterally arranged and equally deposited conducting film connector with a corresponding one of said series of conducting film elements, said conducting connectors being so arranged that by interrupting them selectively the amplitude of said vibrator may be modified in a stepped manner in the desired direction of amplitude increase or decrease.
 2. In an electronic timepiece as claimed in claim 1, wherein said series of conducting elements are originally provided with a plurality of interruptions between said conducting elements, whereby when a selected number of these interruptions are closed by the application of a conducting paste the overall resistance of said resistor unit is reduced to increase the practical amplitude of the mechanical vibrator.
 3. In an electronic timepiece as claimed in claim 1, wherein said series of conducting elements are originally provided with a plurality of conducting joints between said conducting elements, whereby when a selected number of these joints are opened mechanically, the overall resistance of said resistor unit is increased to decrease the practical amplitude of the mechanical vibrator.
 4. In an electronic timepiece as claimed in claim 1, wherein said series of film resistor elements is comprised of an elongated strip of resistor material.
 5. In an electronic timepiece as set forth in claim 1, wherein the drive circuit comprises two transistors which are connected into a multivibrator with each other such that the two coils which are provided in the circuit each act as the sensor and the driver in an alternating way.
 6. In an electronic timepiece as set forth in claim 5, wherein said resistor unit is connected at one end to the collector electrode of one of the transistors and the opposite end of said resistor unit is connected to the base electrode of the remaining resistor as well as one of said coils.
 7. In an electronic timepiece as set forth in claim 6, wherein said resistor unit is doubled in a symmetrical way.
 8. In an electronic timepiece as claimed in claim 1, wherein said resistor unit is so inserted in the circuit that by interrupting said lateral conductive connectors selectively in one direction the overall resistance of the resistor unit is increased correspondingly relative to the drive coil element and by interrupting said lateral conductive connectors selectively in the opposite direction said overall resistance relative to the sensing coil is increased correspondingly. 